2015 Tesla Model S 85D - $144,047EGC

The definition of luxury is a subjective one depending on how much importance you place on individual elements such as style, technology, performance and comfort. Ultimately, a luxury car should possess all of them in equal measure, particularly among the stratosphere where price becomes less an issue.

Last year the Tesla Model S P85+, the game-changing electric car, charged its way past the epitome of luxury, the all-new Mercedes-Benz S-Class, to score Drive's Best Luxury Car over $80,000 title. As a sign of the times, and showcasing the fast-paced development from the ambitious American car maker, the Tesla has already been updated and returns to defend its crown as the P85D with a second electric motor and a host of new high-tech features including an autopilot function.

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Best luxury car over $80,000 2015 Drive Car of the YearTesla's updated Model S defends it crown against high-tech, but traditional, luxury icons from Mercedes-Benz and BMW

Like last year though, it faces off against some established luxury icons; the sportier, more driver focussed (but no-less opulent) S-Class Coupe and BMW's freshly-minted seventh-generation 7-Series limousine, which offers improved levels of quality and driving enjoyment over its predecessor as well as introducing world first technologies and lightweight construction methods.

Even in this company, the Tesla still holds a few aces up its sleeve and has claimed back-to-back victories with four of the six judges giving it the top vote in this class.

Firstly, and in spite of its cutting-edge electric battery pack and the addition of a front-mounted electric motor, it is the most affordable contender here with a sticker of $148,758 (plus on-road costs) and has the lowest running costs with, depending on how, and where, you recharge it, the cheapest energy consumption.

Even still, none of the judges ever felt short-changed in the Tesla. With 311kW of power and 600Nm of torque on offer as soon as you depress the throttle, the Tesla rockets away from a standstill in silent ferocity. And the addition of the front-mounted motor ensures it feels even more planted and secure when you do so, with a phenomenal amount of grip and traction.

More than just its straight line speed, the way the electric motors work makes the Tesla effortless and smooth to drive in normal situations with an equally impressive level of compliance from the suspension.

All the judges liked the Tesla's comprehensive (and comprehensively huge) tablet style centre screen that dominates the dash, and the sheer amount of space inside its cabin and cargo-carrying capacity in its twin boot spaces.

"It's not perfect though," piped one of the judges.

"I still think it lacks the luxury quality and feel of the Germans. It's close, but it doesn't feel like its been 'crafted' like the BMW and Benz."

After much debate, the Tesla pipped the 740i by a single point, making this the closest contest among this year's 15 Drive Car of the Year categories.

The big beemer - a limousine in the most traditional sense - has been designed to be enjoyed from every seat, with a renewed focus on engagement when behind the wheel and comfort and connectivity from every other pew.

On the road, the judges agreed that 740i feels as nimble as a 5-Series - or even a 3-Series - with its variable ratio steering providing a lightness at low speeds that makes it easy to navigate city streets and good weighting at higher speeds to feel secure and sure-footed in the bends. The adaptable air suspension helps too, ironing out almost every bump in its most comfortable setting for relaxed cruising and yet, without compromising its ride quality, it is agile and sits flat under heavy cornering.

Those qualities are, in part, due to the lightness of the 7's multi-material skeleton, which features integrated sections of carbon fibre to keep its overall weight down to just 1800kg - only marginally more than a Holden Commodore SS. The high-strength body also helps cacoon occupants from the outside world, with the 740i almost whisper quiet at speed.

The single-turbo 3.0-litre six cylinder might have the least power in this group - producing 240kW and 450Nm - but it still feels energetic enough and is beautifully mated to the silky smooth eight-speed automatic transmission and its claimed 7.0L/100km fuel consumption figure is more than admirable for such a big car.

Even in the short wheelbase configuration we tested, the 7-Series is a pampering place to sit in the back with comfortable seats cloaked in high-quality leather and featuring more mod cons than you'll ever need, including a tablet that can control functions such as the volume of the audio system and air conditioning as well as surf the internet. It also features world-first gesture command technology where a number of pre-determined functions can be accessed by simple hand movements. While it worked, most judges agreed the novelty wore thin pretty quickly, especially when conventional methods were quicker and more intuitive.

While BMW was praised for including servicing costs in the $224,200 (plus on-road) sticker price for the 7-Series, the judges' marked it down for its alarming 38.4 percent forecasted retained value after three years of ownership, which is no doubt a result of its popularity with hire car operators more than an indictment on its long-term quality and reliability.

Value for money was also a cloud that hung over the S500 Coupe and, ultimately, weighed it down on to the bottom step of the podium in this contest. At $318,610 (plus on-road costs), it was the most expensive finalist in the entire Drive Car of the Year field.

But you get what you pay for, and the S-Class Coupe is undeniably opulent in its luxury, refined in its driving character and sublime in its performance.

Its 4.7-litre twin-turbo V8 is the most powerful engine here, producing 335kW and 700Nm, and the judges all agreed that it was a beautiful motor that perfectly suited the character of the car, and that its nine-speed automatic ensured it either wafted along without any fuss or tapped into its huge reserves of torque quickly when called upon.

But it is a big car, and even with all of its electronic trickery - including air suspension that tilts the car in the opposite direction during hard cornering so it leans into the bend like a motorcycle - it can't hide its sheer mass.

Not surprisingly, it was also the most expensive to run, with an average fuel consumption of 8.6L/100km (which is still amazing for a car of this size and with that much power) and the highest servicing costs. Both of which are offset though by the fact it has the highest forecasted retained value in the entire field at 64.3 percent.

Nothing, however, could halt the Tesla from plugging its way into victory lane as Drive's Best Luxury Car over $80,000 for the second consecutive year.